Add support for the DECSCNM screen mode

src/host/getset.cpp

@@ -1291,6 +1291,35 @@ void ApiRoutines::GetConsoleDisplayModeImpl(ULONG& flags) noexcept
     return STATUS_SUCCESS;
 }
 
+// Routine Description:
+// - A private API call for changing the screen mode between normal and reverse.
+//    When in reverse screen mode, the background and foreground colors are switched.
+// Parameters:
+// - reverseMode - set to true to enable reverse screen mode, false for normal mode.
+// Return value:
+// - STATUS_SUCCESS if handled successfully. Otherwise, an appropriate error code.
+[[nodiscard]] NTSTATUS DoSrvPrivateSetScreenMode(const bool reverseMode)
+{
+    try
+    {
+        Globals& g = ServiceLocator::LocateGlobals();
+        CONSOLE_INFORMATION& gci = g.getConsoleInformation();
+
+        gci.SetScreenReversed(reverseMode);
+
+        if (g.pRender)
+        {
+            g.pRender->TriggerRedrawAll();
+        }
+
+        return STATUS_SUCCESS;
+    }
+    catch (...)
+    {
+        return NTSTATUS_FROM_HRESULT(wil::ResultFromCaughtException());
+    }
+}
+
 // Routine Description:
 // - A private API call for making the cursor visible or not. Does not modify
 //      blinking state.

src/host/getset.h

@@ -29,6 +29,8 @@ void DoSrvPrivateSetDefaultAttributes(SCREEN_INFORMATION& screenInfo, const bool
 [[nodiscard]] NTSTATUS DoSrvPrivateSetCursorKeysMode(_In_ bool fApplicationMode);
 [[nodiscard]] NTSTATUS DoSrvPrivateSetKeypadMode(_In_ bool fApplicationMode);
 
+[[nodiscard]] NTSTATUS DoSrvPrivateSetScreenMode(const bool reverseMode);
+
 void DoSrvPrivateShowCursor(SCREEN_INFORMATION& screenInfo, const bool show) noexcept;
 void DoSrvPrivateAllowCursorBlinking(SCREEN_INFORMATION& screenInfo, const bool fEnable);
 

src/host/outputStream.cpp

@@ -345,6 +345,19 @@ bool ConhostInternalGetSet::PrivateSetKeypadMode(const bool fApplicationMode)
     return NT_SUCCESS(DoSrvPrivateSetKeypadMode(fApplicationMode));
 }
 
+// Routine Description:
+// - Connects the PrivateSetScreenMode call directly into our Driver Message servicing call inside Conhost.exe
+//   PrivateSetScreenMode is an internal-only "API" call that the vt commands can execute,
+//     but it is not represented as a function call on our public API surface.
+// Arguments:
+// - reverseMode - set to true to enable reverse screen mode, false for normal mode.
+// Return Value:
+// - true if successful (see DoSrvPrivateSetScreenMode). false otherwise.
+bool ConhostInternalGetSet::PrivateSetScreenMode(const bool reverseMode)
+{
+    return NT_SUCCESS(DoSrvPrivateSetScreenMode(reverseMode));
+}
+
 // Routine Description:
 // - Connects the PrivateShowCursor call directly into our Driver Message servicing call inside Conhost.exe
 //   PrivateShowCursor is an internal-only "API" call that the vt commands can execute,

src/host/outputStream.hpp

@@ -93,6 +93,8 @@ class ConhostInternalGetSet final : public Microsoft::Console::VirtualTerminal::
     bool PrivateSetCursorKeysMode(const bool applicationMode) override;
     bool PrivateSetKeypadMode(const bool applicationMode) override;
 
+    bool PrivateSetScreenMode(const bool reverseMode) override;
+
     bool PrivateShowCursor(const bool show) noexcept override;
     bool PrivateAllowCursorBlinking(const bool enable) override;
 

src/host/settings.cpp

@@ -53,6 +53,7 @@ Settings::Settings() :
     _fUseWindowSizePixels(false),
     _fAutoReturnOnNewline(true), // the historic Windows behavior defaults this to on.
     _fRenderGridWorldwide(false), // historically grid lines were only rendered in DBCS codepages, so this is false by default unless otherwise specified.
+    _fScreenReversed(false),
     // window size pixels initialized below
     _fInterceptCopyPaste(0),
     _DefaultForeground(INVALID_COLOR),
@@ -394,6 +395,15 @@ void Settings::SetGridRenderingAllowedWorldwide(const bool fGridRenderingAllowed
     }
 }
 
+bool Settings::IsScreenReversed() const
+{
+    return _fScreenReversed;
+}
+void Settings::SetScreenReversed(const bool fScreenReversed)
+{
+    _fScreenReversed = fScreenReversed;
+}
+
 bool Settings::GetFilterOnPaste() const
 {
     return _fFilterOnPaste;
@@ -942,7 +952,14 @@ COLORREF Settings::CalculateDefaultBackground() const noexcept
 COLORREF Settings::LookupForegroundColor(const TextAttribute& attr) const noexcept
 {
     const auto tableView = std::basic_string_view<COLORREF>(&GetColorTable()[0], GetColorTableSize());
-    return attr.CalculateRgbForeground(tableView, CalculateDefaultForeground(), CalculateDefaultBackground());
+    if (_fScreenReversed)
+    {
+        return attr.CalculateRgbBackground(tableView, CalculateDefaultForeground(), CalculateDefaultBackground());
+    }
+    else
+    {
+        return attr.CalculateRgbForeground(tableView, CalculateDefaultForeground(), CalculateDefaultBackground());
+    }
 }
 
 // Method Description:
@@ -955,7 +972,14 @@ COLORREF Settings::LookupForegroundColor(const TextAttribute& attr) const noexce
 COLORREF Settings::LookupBackgroundColor(const TextAttribute& attr) const noexcept
 {
     const auto tableView = std::basic_string_view<COLORREF>(&GetColorTable()[0], GetColorTableSize());
-    return attr.CalculateRgbBackground(tableView, CalculateDefaultForeground(), CalculateDefaultBackground());
+    if (_fScreenReversed)
+    {
+        return attr.CalculateRgbForeground(tableView, CalculateDefaultForeground(), CalculateDefaultBackground());
+    }
+    else
+    {
+        return attr.CalculateRgbBackground(tableView, CalculateDefaultForeground(), CalculateDefaultBackground());
+    }
 }
 
 bool Settings::GetCopyColor() const noexcept

src/host/settings.hpp

@@ -52,6 +52,9 @@ class Settings
     bool IsGridRenderingAllowedWorldwide() const;
     void SetGridRenderingAllowedWorldwide(const bool fGridRenderingAllowed);
 
+    bool IsScreenReversed() const;
+    void SetScreenReversed(const bool fScreenReversed);
+
     bool GetFilterOnPaste() const;
     void SetFilterOnPaste(const bool fFilterOnPaste);
 
@@ -231,6 +234,7 @@ class Settings
     DWORD _dwVirtTermLevel;
     bool _fAutoReturnOnNewline;
     bool _fRenderGridWorldwide;
+    bool _fScreenReversed;
     bool _fUseDx;
     bool _fCopyColor;
 

src/host/ut_host/ScreenBufferTests.cpp

@@ -180,6 +180,7 @@ class ScreenBufferTests
 
     TEST_METHOD(ScrollLines256Colors);
 
+    TEST_METHOD(SetScreenMode);
     TEST_METHOD(SetOriginMode);
 
     TEST_METHOD(HardResetBuffer);
@@ -4409,6 +4410,34 @@ void ScreenBufferTests::ScrollLines256Colors()
     }
 }
 
+void ScreenBufferTests::SetScreenMode()
+{
+    auto& gci = ServiceLocator::LocateGlobals().getConsoleInformation();
+    auto& si = gci.GetActiveOutputBuffer();
+    auto& stateMachine = si.GetStateMachine();
+
+    const auto rgbForeground = RGB(12, 34, 56);
+    const auto rgbBackground = RGB(78, 90, 12);
+    const auto testAttr = TextAttribute{ rgbForeground, rgbBackground };
+
+    Log::Comment(L"By default the screen mode is normal.");
+    VERIFY_IS_FALSE(gci.IsScreenReversed());
+    VERIFY_ARE_EQUAL(rgbForeground, gci.LookupForegroundColor(testAttr));
+    VERIFY_ARE_EQUAL(rgbBackground, gci.LookupBackgroundColor(testAttr));
+
+    Log::Comment(L"When DECSCNM is set, background and foreground colors are switched.");
+    stateMachine.ProcessString(L"\x1B[?5h");
+    VERIFY_IS_TRUE(gci.IsScreenReversed());
+    VERIFY_ARE_EQUAL(rgbBackground, gci.LookupForegroundColor(testAttr));
+    VERIFY_ARE_EQUAL(rgbForeground, gci.LookupBackgroundColor(testAttr));
+
+    Log::Comment(L"When DECSCNM is reset, the colors are normal again.");
+    stateMachine.ProcessString(L"\x1B[?5l");
+    VERIFY_IS_FALSE(gci.IsScreenReversed());
+    VERIFY_ARE_EQUAL(rgbForeground, gci.LookupForegroundColor(testAttr));
+    VERIFY_ARE_EQUAL(rgbBackground, gci.LookupBackgroundColor(testAttr));
+}
+
 void ScreenBufferTests::SetOriginMode()
 {
     auto& gci = ServiceLocator::LocateGlobals().getConsoleInformation();

src/terminal/adapter/DispatchTypes.hpp

@@ -82,6 +82,7 @@ namespace Microsoft::Console::VirtualTerminal::DispatchTypes
     {
         DECCKM_CursorKeysMode = 1,
         DECCOLM_SetNumberOfColumns = 3,
+        DECSCNM_ScreenMode = 5,
         DECOM_OriginMode = 6,
         ATT610_StartCursorBlink = 12,
         DECTCEM_TextCursorEnableMode = 25,

src/terminal/adapter/ITermDispatch.hpp

@@ -52,6 +52,7 @@ class Microsoft::Console::VirtualTerminal::ITermDispatch
     virtual bool SetCursorKeysMode(const bool applicationMode) = 0; // DECCKM
     virtual bool SetKeypadMode(const bool applicationMode) = 0; // DECKPAM, DECKPNM
     virtual bool EnableCursorBlinking(const bool enable) = 0; // ATT610
+    virtual bool SetScreenMode(const bool reverseMode) = 0; //DECSCNM
     virtual bool SetOriginMode(const bool relativeMode) = 0; // DECOM
     virtual bool SetTopBottomScrollingMargins(const size_t topMargin, const size_t bottomMargin) = 0; // DECSTBM
     virtual bool ReverseLineFeed() = 0; // RI

src/terminal/adapter/adaptDispatch.cpp

@@ -1066,6 +1066,9 @@ bool AdaptDispatch::_PrivateModeParamsHelper(const DispatchTypes::PrivateModePar
     case DispatchTypes::PrivateModeParams::DECCOLM_SetNumberOfColumns:
         success = _DoDECCOLMHelper(enable ? DispatchTypes::s_sDECCOLMSetColumns : DispatchTypes::s_sDECCOLMResetColumns);
         break;
+    case DispatchTypes::PrivateModeParams::DECSCNM_ScreenMode:
+        success = SetScreenMode(enable);
+        break;
     case DispatchTypes::PrivateModeParams::DECOM_OriginMode:
         // The cursor is also moved to the new home position when the origin mode is set or reset.
         success = SetOriginMode(enable) && CursorPosition(1, 1);
@@ -1212,6 +1215,18 @@ bool AdaptDispatch::DeleteLine(const size_t distance)
     return _pConApi->DeleteLines(distance);
 }
 
+// Routine Description:
+// - DECSCNM - Sets the screen mode to either normal or reverse.
+//    When in reverse screen mode, the background and foreground colors are switched.
+// Arguments:
+// - reverseMode - set to true to enable reverse screen mode, false for normal mode.
+// Return Value:
+// - True if handled successfully. False otherwise.
+bool AdaptDispatch::SetScreenMode(const bool reverseMode)
+{
+    return _pConApi->PrivateSetScreenMode(reverseMode);
+}
+
 // Routine Description:
 // - DECOM - Sets the cursor addressing origin mode to relative or absolute.
 //    When relative, line numbers start at top margin of the user-defined scrolling region.
@@ -1562,6 +1577,12 @@ bool AdaptDispatch::HardReset()
         success = _EraseScrollback();
     }
 
+    // Set the DECSCNM screen mode back to normal.
+    if (success)
+    {
+        success = SetScreenMode(false);
+    }
+
     // Cursor to 1,1 - the Soft Reset guarantees this is absolute
     if (success)
     {

src/terminal/adapter/adaptDispatch.hpp

@@ -66,6 +66,7 @@ namespace Microsoft::Console::VirtualTerminal
         bool SetCursorKeysMode(const bool applicationMode) override; // DECCKM
         bool SetKeypadMode(const bool applicationMode) override; // DECKPAM, DECKPNM
         bool EnableCursorBlinking(const bool enable) override; // ATT610
+        bool SetScreenMode(const bool reverseMode) override; //DECSCNM
         bool SetOriginMode(const bool relativeMode) noexcept override; // DECOM
         bool SetTopBottomScrollingMargins(const size_t topMargin,
                                           const size_t bottomMargin) override; // DECSTBM

src/terminal/adapter/conGetSet.hpp

@@ -57,6 +57,8 @@ namespace Microsoft::Console::VirtualTerminal
         virtual bool PrivateSetCursorKeysMode(const bool applicationMode) = 0;
         virtual bool PrivateSetKeypadMode(const bool applicationMode) = 0;
 
+        virtual bool PrivateSetScreenMode(const bool reverseMode) = 0;
+
         virtual bool PrivateShowCursor(const bool show) = 0;
         virtual bool PrivateAllowCursorBlinking(const bool enable) = 0;
 

src/terminal/adapter/termDispatch.hpp

@@ -46,6 +46,7 @@ class Microsoft::Console::VirtualTerminal::TermDispatch : public Microsoft::Cons
     bool SetCursorKeysMode(const bool /*applicationMode*/) noexcept override { return false; } // DECCKM
     bool SetKeypadMode(const bool /*applicationMode*/) noexcept override { return false; } // DECKPAM, DECKPNM
     bool EnableCursorBlinking(const bool /*enable*/) noexcept override { return false; } // ATT610
+    bool SetScreenMode(const bool /*reverseMode*/) noexcept override { return false; } //DECSCNM
     bool SetOriginMode(const bool /*relativeMode*/) noexcept override { return false; }; // DECOM
     bool SetTopBottomScrollingMargins(const size_t /*topMargin*/, const size_t /*bottomMargin*/) noexcept override { return false; } // DECSTBM
     bool ReverseLineFeed() noexcept override { return false; } // RI

src/terminal/adapter/ut_adapter/adapterTest.cpp

@@ -162,6 +162,13 @@ class TestGetSet final : public ConGetSet
         return _privateSetKeypadModeResult;
     }
 
+    bool PrivateSetScreenMode(const bool /*reverseMode*/) override
+    {
+        Log::Comment(L"PrivateSetScreenMode MOCK called...");
+
+        return true;
+    }
+
     bool PrivateShowCursor(const bool show) override
     {
         Log::Comment(L"PrivateShowCursor MOCK called...");

src/terminal/parser/ut_parser/OutputEngineTest.cpp

@@ -676,6 +676,7 @@ class StatefulDispatch final : public TermDispatch
         _isAltBuffer{ false },
         _cursorKeysMode{ false },
         _cursorBlinking{ true },
+        _isScreenModeReversed{ false },
         _isOriginModeRelative{ false },
         _isDECCOLMAllowed{ false },
         _windowWidth{ 80 },
@@ -835,6 +836,9 @@ class StatefulDispatch final : public TermDispatch
         case DispatchTypes::PrivateModeParams::DECCOLM_SetNumberOfColumns:
             fSuccess = SetColumns(static_cast<size_t>(fEnable ? DispatchTypes::s_sDECCOLMSetColumns : DispatchTypes::s_sDECCOLMResetColumns));
             break;
+        case DispatchTypes::PrivateModeParams::DECSCNM_ScreenMode:
+            fSuccess = SetScreenMode(fEnable);
+            break;
         case DispatchTypes::PrivateModeParams::DECOM_OriginMode:
             // The cursor is also moved to the new home position when the origin mode is set or reset.
             fSuccess = SetOriginMode(fEnable) && CursorPosition(1, 1);
@@ -898,6 +902,12 @@ class StatefulDispatch final : public TermDispatch
         return true;
     }
 
+    bool SetScreenMode(const bool reverseMode) noexcept override
+    {
+        _isScreenModeReversed = reverseMode;
+        return true;
+    }
+
     bool SetOriginMode(const bool fRelativeMode) noexcept override
     {
         _isOriginModeRelative = fRelativeMode;
@@ -949,6 +959,7 @@ class StatefulDispatch final : public TermDispatch
     bool _isAltBuffer;
     bool _cursorKeysMode;
     bool _cursorBlinking;
+    bool _isScreenModeReversed;
     bool _isOriginModeRelative;
     bool _isDECCOLMAllowed;
     size_t _windowWidth;
@@ -1226,6 +1237,25 @@ class StateMachineExternalTest final
         pDispatch->ClearState();
     }
 
+    TEST_METHOD(TestScreenMode)
+    {
+        auto dispatch = std::make_unique<StatefulDispatch>();
+        auto pDispatch = dispatch.get();
+        auto engine = std::make_unique<OutputStateMachineEngine>(std::move(dispatch));
+        StateMachine mach(std::move(engine));
+
+        mach.ProcessString(L"\x1b[?5h");
+        VERIFY_IS_TRUE(pDispatch->_isScreenModeReversed);
+
+        pDispatch->ClearState();
+        pDispatch->_isScreenModeReversed = true;
+
+        mach.ProcessString(L"\x1b[?5l");
+        VERIFY_IS_FALSE(pDispatch->_isScreenModeReversed);
+
+        pDispatch->ClearState();
+    }
+
     TEST_METHOD(TestOriginMode)
     {
         auto dispatch = std::make_unique<StatefulDispatch>();